Improper Installation of RV Roof

I recently had my rubber roof replaced on my Class C, 22-foot motorhome. The rubber was still good but getting old. But because the old plywood was bonded to foam insulation, they put plywood over it and installed the new rubber roof. Within four months the plywood under the rubber warped really bad. They say they will fix it under warranty but I was curious as to how they do this as it seems the plywood didn't hold the first time around. It's been in the shop over two weeks now and I cannot find anything out yet. How will they attempt to solve this problem? BMCM, (FL)

It’s difficult to ascertain just how they installed that new substrate plywood to the older roof. Hopefully, they removed the rubber membrane, inspected the older substrate plywood for damage, then glued and screwed the new plywood directly to the old plywood after properly preparing it. The condition of the old plywood is crucial. If they attached the new wood to a deteriorated or moisture-damaged substrate, it’s possible the new plywood would buckle in places. It sounds like this may be the case.

They will have to remove the new membrane and the new plywood and thoroughly inspect the old substrate to determine the best course of action before continuing. It is salvageable for sure, but to avoid future issues, it must be done correctly this time. I would also insist on a new membrane. Once they remove the rubber from the new plywood, it will have stretched and been rendered unusable.

Let me know how it turns out. It’s great that they will at least honor their warranty! But they must prepare the old roof properly prior to installing the new roof substrate and EPDM membrane.